True A median filter is a non- linear filter is used for signal smoothing. It is particularly good for removing impulsive type noise from the signal. There are a number of variations of this filter and a two dimensional variant is often used in digital image processing systems to remove noise and speckles from images. The non-linear function of the median filter can be expressed as:

y(n) = med [x(n-k), x(n-k+1),…..x(n),….x(n+k-1), s(n+k)]……(i)

Where y(n) is the output and x(n) the input signal. The filter collects a window containing N=2k+1 samples of te input signal and then performs the median operator on this set of samples. Taking the median means to sort the samples by magnitude and then select the mid-value samples must be used in the window, the median is define as given. Assuming the samples are sorted in such a way that x1 is the smallest and x2k+1 the largest value.